The present invention relates to a disk apparatus which records and reproduces on/from a rotatable disk medium. More particularly, it relates to a disk apparatus which is preferable when a thin magneto-optic disk apparatus is constructed.
Conventionally, a magnetic disk apparatus which performs recording and reproducing on/from a 3.5-inch magnetic disk medium provided rotatably in a hard case is used with the hard disk apparatus built in various computers and word processors. Such apparatus has been generally identified as an external storage device.
A 3.5-inch magneto-optic disk medium used for a magneto-optic disk apparatus has substantially the same shape as that of the magnetic disk medium, however, it is contained in a hard case where the thickness and chamfer portion are different from those of the magnetic disk.
Referring to the figures, the configuration of the magneto-optic disk apparatus is described below. FIG. 1A is a top view of the magneto-optic disk 100, FIG. 1B is a side view of the magneto-optic disk 100, and FIG. 1C is a bottom view of the magneto-optic disk 100. As shown in FIGS. 1A through 1C, the magneto-optic disk 100 consists of a hard case 100a made from resin of, and a disk medium 120 indicated by a broken line which is built-in rotatably. The disk medium 120 is accessible outside through a large opening 104 (refer to FIG. 1A) and small opening 109 (refer to FIG. 1B) so as to perform the open/close operation of a shutter 103 which is integrated with the magneto-optic disk 100.
While turning effort is transmitted to the disk medium 120 by a chucking of the central portion of the disk medium 120 through the large opening 104, the magneto-optic disk 100 is initialized by exposing the disk medium 120 to an external magnetic field through the small opening 109.
The shutter 103 is constituted by bending a stainless metallic plate made of a non-magnetic material in a U-shape, and thus, a face portion 103a and back portion 103b of the shutter 103 are formed as a unit. Furthermore, the face portion 103a and back portion 103b are incorporated into a slide portion 103c which is set into a guide groove formed on the side face of the hard case 100a.
With the above arrangement, when the shutter 103 is opened, an end of the slide portion 103c is pressed and slid by a pin inserted in a slanting surface 112 of the case against the resistance of an energized member (not shown). The closed shutter 103 as shown in FIG. 1C is slid in the arrow's direction to be opened.
At the corner of the hard case 100a, a chamfer 107 is formed so as to avoid inserting the disk medium 120 upside down. Furthermore, in the back side of the hard case 100a, a pair of reference concavities 101 and 102 are provided so as to be a reference line in the direction of XY of the magneto-optic disk 100 in order to reserve each reference size (56, 53, 55, 54 mm) for chucking and obtain a reference face P after the chucking. Furthermore, the hard case 100a is provided with semi-circle concavities 105 and 106 and concavities 110 and 111 which are engaging portions when the disk medium 120 is inserted/ejected in an automatic disk apparatus.
The thickness of the resin hard case 100a is approximately 6 mm and it is essentially twice as thick as that of the 3.5-inch magnetic disk media. The above magneto-optic disk 100 has been recently determined as an International Standard.